Cardiovascular disease (CVD) is the leading cause of death among Hispanics residing in the U.S., contributing to nearly one of every four deaths. Most studies on Hispanics have focused on Mexican Americans and, with the exception of the Puerto Rico Heart Study, which was conducted on the island of Puerto Rico several decades ago;few have explored CVD risk factors in Puerto Ricans. Importantly, the Puerto Rican population differs considerably in ancestral genetic history, and in exposures to known risk factors for these important prevalent conditions from other Hispa:nic groups. Differing risk factors include unique dietary intake and physical activity patterns, as well as social, cultural and environmental structures that contribute to and affect CVD risk. The high poverty rates and majority urban environment contribute to these processes in unknown ways: As this group is both a rapidly growing and aging subset ofthe US population, the significance of understanding the reasons for the considerably higher prevalence and incidence of cardiovascular risk factors in this high risk population is critical. The rationale is that these associations are complex and likely iterative, requiring longitudinal analyses in order to understand causal direction and to fully implement multilevel analyses. Our overall aim for this project is to prospectively follow participants ofthe Boston Puerto Rican Health Study for 5 years to measure progression of CVD risk factors and of sub-clinical markers of CVD, so that we may clarify the causal direction of identified associations. We aim to assess five year prospective interrelationships (3 time points) between dietary pattern and vitamin (folate, vitamin B6, vitamin B12, vitamin D, total carotenoids) intake and plasma status and progression of CVD risk factors (pulse pressure, hypertension, and Framingham Risk score (FRS)); assess associations between dietary intake pattern and vitamin status across three time points with CVD indicators, (ABI and IMT) at the 5-year time point;measure associations between allostatic load and FRS with ABI and IMT at 5 years;measure associations between measures of neighborhood environment for healthy food availability and walkability with dietary intake pattern, obesity measures, allostatic load, CVD risk factors, and CVD indicators. Preliminary data show that Puerto Ricans have a high prevalence of comorbidities, particularly hypertension, depression and diabetes. We have also documented multiple social and environmental disparities and a unique genetic background for this ethnic group. Longitudinal studies, as proposed, are critical to untangle the complexities ofthe multiple CVD risk factors and their progression toward health outcomes. Our proposed project is of paramount importance, as understanding the unique contributors to disease and the needs of this large, high-risk group will allow for targeted public health action toward decreasing CVD and improving overall health in this population. Our study may provide insights and serve as a model for future multidisciplinary approaches in other vulnerable groups.